Short communicationInfluence of V-sources on the catalytic performance of VMCM-41 in the selective oxidation of methane to formaldehyde

- VMCM-41 catalysts were used for the selective oxidation of methane to formaldehyde.
- VO(acac)2 as V precursor leads to monomeric VOx species.
- VOSO4 as V precursor leads to increasing portion of oligomeric VOx species.
- VMCM-41 from VO(acac)2 converts up to five times more methane.
- A high space time yield of 5.3 kgCH2O·kgcat− 1·h− 1 was obtained.

VMCM-41 catalysts from two different tetravalent vanadium sources, hydrothermally synthesized after a mild gelation step at room temperature, were used as catalysts for the selective oxidation of methane to formaldehyde. Vanadyl acetylacetonate as VMCM-41 precursor, facilitates highest VOx density with predominance of monomeric and a small portion of low-oligomeric VOx species. It produces CH2O in high yield and the highest space time yield (STYCH2O) reaches 5.3 kgCH2O·kgcat− 1·h− 1 at 600 °C (rate of formation, rCH2O of 363 h− 1). VMCM-41 synthesized from vanadyl sulfate hydrate precursor contains a more significant portion of low-oligomeric species. With a lower V loading, these VOx species are significantly less active resulting in a maximum STYCH2O of 2.7 kgCH2O·kgcat− 1·h− 1 at 625 °C (rCH2O of 243 h− 1).